I've been trying to code something using the new experimental feature "modules-ts" that will be included in c++20. I've cloned the gcc branch (found here: https://gcc.gnu.org/wiki/cxx-modules), and I'm trying to follow that tutorial (on the link) using modules-ts but an g++ error is preventing me from doing that:
g++: error: unrecognized command-line option ‘-fmodules-ts’
I tried to see the version of g++, to make sure that is not reading from another previous version. And the answer is:
g++ (GCC) 10.0.0 20191029 (experimental)
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Here is the command that I'm trying to run:
g++ -fmodules-ts hello.cppm main.cpp
Modules-ts is not merged into GCC's main branch yet. You need to download GCC's source and compile it yourself, for further instructions see GCC's installation guide. Grab the source using
svn co svn://gcc.gnu.org/svn/gcc/branches/c++-modules SomeLocalDir
instead of
svn checkout svn://gcc.gnu.org/svn/gcc/trunk SomeLocalDir
and you'll get the correct version.
EDIT:
For clarification, in this answer I assumed the OP did not compile the right GCC version because there is no svn revision number inside his gcc --version.
Related
I have run in an issue with compiling gdb from source. I am downloading version 8.2.1 but when I try to compile it, I get the following error:
configure: error: *** A compiler with support for C++11 language features is required.
make[1]: *** [configure-gdb] Error 1
My operating system is Red Hat 7.6 (Maipo) but i have a compiled from source gcc(that i set as the default one with an alias in bashrc)
gcc --version
gcc (GCC) 8.2.0
Copyright (C) 2018 Free Software Foundation, Inc.
which gcc
alias gcc='/usr/local/gcc8.2/bin/gcc'
/usr/local/gcc8.2/bin/gcc
which g++
alias g++='/usr/local/gcc8.2/bin/g++'
/usr/local/gcc8.2/bin/g++
What i have tried/read so far
Read the gdb manual regarding the configure and instalation part, also various stackoverflow links but nobody seems to have this problem
Read the README file in the gdb folder/subfolders
Tried setting the following env options CXX_FOR_TARGET=/usr/local/gcc8.2/bin/g++ GCC_FOR_TARGET=/usr/local/gcc8.2/bin/gcc (not sure if i should replace target with my actual target architecture)
Looked in the gdb-8.2.1 folder at the file config.log and found these: ac_cv_env_GCC_FOR_TARGET_value=/usr/local/gcc8.2/bin/gcc
ac_cv_prog_CXX_FOR_TARGET=/usr/local/gcc8.2/bin/g++
ac_cv_prog_GCC_FOR_TARGET=/usr/local/gcc8.2/bin/gcc
However in the C compiler section of the same config log I have found the following:
configure:4284: checking for C compiler version
configure:4293: gcc --version >&5
gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-36)
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
I am not sure ifi can use the devtoolset-8 gdb from RedHat because i have compiled gcc with GLIBCXX_USE_CXX11_ABI=1 and on RedHat due to a bug this is disabled by default and i am not sure if gdb will be able to manage the different binary interface.
Short version: What am I doing wrong that is making the GDB configure script not find the correct compiler and how can i fix/workaround this?
Thank you very much for your help!
A C++11-capable compiler for Red Hat Enterprise Linux 7 is provided as part of Red Hat Developer Toolset. It happens to include not just GCC 8, but GDB 8.2 as well, so you may not even have to compile it yourself. The DTS C++ compiler has been built in a special way so that it interoperates with the system C++ runtime. Unless you have replicated those modifications in your GCC build, it will not be compatible with the rest of the system (and you will have to replace the system libstdc++ library).
The system compiler in Red Hat Enterprise Linux 7 is based on GCC 4.8. In that version, C++11 support was still experimental and not enabled by default. You can try to configure GDB with
./configure CXX="g++ -std=gnu+11"
but this is not recommended (only the C++98 mode is supported).
The configure script does not use shell aliases because those are not inherited by shell scripts invoked from a shell. You will have to specify the full path to the C++ compiler explicitly (in the CXX= argument to configure), or adjust the PATH environment variable manually, or use scl enable to do so in a more polished fashion (for software collections such as Developer Toolset).
The Problem:
I'm trying to install a program called mapnik from source on CentOS 7. When I run ./configure I get the following error.
C++ compiler does not support C++11 standard (-std=c++11), which is required. Please upgrade your compiler to at least g++ 4.7 (ideally 4.8)
Unfortunately its not as simple as just updating gcc because when I run:
gcc --version
I get:
gcc (GCC) 4.8.3 20140911 (Red Hat 4.8.3-9)
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
How can I fix this? Thanks in advance.
Well, your GCC version is from 2013, so there is certainly room for update.
Furthermore(i might be mistaken here), don't you need g++ to compile C++? This would work the following way:
sudo yum install g++
The Soultion:
I ended up just removing all of Mapnik which I cloned from their git page, and instead downloaded the latest tar.gz version. From there I just installed like normal and it worked. Not the most intuitive fix, but it did the job.
I am using centos 6.5 which has a cmake 2.6.
I want to upgrade to higher version (cmake 2.8 or cmake 3.0).
I have the downloaded the setup files.
When i run the file using ./configure i get the following error message
[root#dtl-sameet cmake-3.0.0]# ./configure
---------------------------------------------
CMake 3.0.0, Copyright 2000-2014 Kitware, Inc.
C compiler on this system is: gcc
---------------------------------------------
Error when bootstrapping CMake:
Cannot find appropriate C++ compiler on this system.
Please specify one using environment variable CXX.
See cmake_bootstrap.log for compilers attempted.
---------------------------------------------
Log of errors: /home/sameet/Downloads/cmake-3.0.0/Bootstrap.cmk/cmake_bootstrap.log
I have updated the gcc to higher version and i want to keep this higher version
[root#dtl-sameet cmake-3.0.0]# gcc --version
gcc (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[root#dtl-sameet cmake-3.0.0]# g++ --version
g++ (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The link answers the similar question but i did not wanted to install "Development Tools" as this would make gcc fall back to old version.
This link answers the similar question but i did not wanted install a package manager.
I set the environmental variable for CXX as
export CXX="/usr/bin/gcc"
It did not work.
Look into Bootstrap.cmk/cmake_bootstrap.log.
The configure script runs a number of tests. I assume that one of them failed.
You need to find out which one, what the test does and how to make it work or disable it.
You might want to update your question and hopefully someone will find out what is wrong with the cmake bootstrap on your system.
I am trying to cross-compile some code for an i.mx51 platform.
I am using gcc provided by freescale for the platform, see below:
user#:/media/sf_repos/1109$ /opt/freescale/usr/local/gcc-4.1.2-glibc-2.5-nptl-3/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc --version
arm-none-linux-gnueabi-gcc (GCC) 4.1.2
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The makefile which I am using utilizes the # flag which is available in GCC.
#FILE Read options from FILE
But using the provided gcc and using #FILE to point to my commands file, I get:
arm-none-linux-gnueabi-gcc: #hello.o_command: No such file or directory
arm-none-linux-gnueabi-gcc: no input files
(I know that this question may be too specific)
Does anyone have any idea about this issue? In the -v --help I can see that #FILE is mentioned so it should be supported!
OK, I managed to find the answer myself.
# was introduced in gcc 4.2.1. See the documentation.
So my compiler which is based on gcc 4.1.2 does not support it.
When I run g++ --version on in my Cloud9 terminal I get g++ (GCC) 4.4.7 20120313 (Red Hat 4.4.7-3). This is a fairly old version - old enough that when I try to use C++11 library features like std::unordered_set, I get: "This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently experimental, and must be enabled with the -std=c++0x or -std=gnu++0x compiler options."
I'm not really okay with this, because I don't like having to worry about what features I'm allowed to use and which ones I need to avoid. So I went looking around for how to update g++ to the latest stable version (which seems to be 4.8.1 as of this writing), but I can't figure out how to do it. I tried apt-get, but I just got an error: "Sorry, apt-get is not supported on this system. Try c9pm instead.". Well I tried that, but c9pm list (which is supposed to "List available packages") doesn't show anything that looks like g++. So I'm lost.
How do I install g++ 4.8.1 on Cloud9?
When I run lsb_release -a I see that Cloud9 IDE currently runs on "Red Hat Enterprise Linux Server release 6.4 (Santiago)".
If you choose C/C++ as the project type for a new project you will get a newer gcc version (currently 4.7.2). If you need an even newer one let us know and we can update that version. You can always try to compile the tools you need on the workspace but in case of gcc this might take ages.
This is no longer a problem. g++ --version now returns g++ (Ubuntu 4.8.2-19ubuntu1) 4.8.2 which, to my knowledge, has full support for C++11.
Actually, cloud9 gives you 4.8.2
cpp --version
cpp (Ubuntu 4.8.2-19ubuntu1) 4.8.2
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.